Drift scooter

ABSTRACT

A drift scooter comprising a longitudinal frame including opposed leading and trailing end portions. A steering assembly is pivotably disposed on the leading end portion and includes a transverse member with two wheels rotatably supported on opposite ends of the transverse member. A stem is fixed in perpendicular orientation relative to the transverse member and a handlebar is connected to the stem. A rear wheel assembly is pivotably disposed on the trailing end portion, wherein the wheel assembly pivots about an upwardly extending pivot axis. The rear wheel assembly is preferably biased toward a centered position, aligned with a centerline of the frame. A resilient member is connected between the frame and a leading portion of the caster. The resilient member may be in the form of an extension spring. Means for adjusting the tension of the extension spring may also be included.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.12/750,163, titled “DRIFT SCOOTER”, filed on Mar. 30, 2010, which isincorporated herein by reference in its entirety.

BACKGROUND

Non-motorized foot board scooters are known in the art. These scootersgenerally include a front wheel aligned with a back wheel, with each ofthe wheels being attached to a frame. The frame generally comprises aflat surface located between the two wheels for the rider to stand onand a steering assembly rising vertically from the front or leading endof the frame. The steering assembly is attached at one end to the frontwheel for front wheel steering of the scooter and terminates at theother end in handle bars for the rider to use to steer the scooter.Forward movement of these non-motorized foot board scooters is normallyachieved by the rider taking one foot off the flat surface and pushingagainst the ground with the foot removed from the flat surface to beginforward movement of the scooter. In order to negotiate turns on thetypical scooter the rider turns the front wheel while leaning into theturn such that the front and rear wheels track along an arc in the usualmanner. The turning style of the typical scooter is similar to that ofriding a bicycle, for example.

While enjoyable to ride, the typical scooter design merely provides thesame predictable cornering experience that is well known in the art.Accordingly, there exists a demand for a scooter that provides a new andexciting cornering sensation that enhances the rider's enjoyment inriding the scooter.

SUMMARY

Described herein are various embodiments of a drift scooter. Generally,the drift scooter comprises a longitudinal frame including opposedleading and trailing end portions. The scooter may include a deckextending along at least a portion of the frame. Preferably, the topsurface of the deck includes a convex portion.

A steering assembly is pivotably disposed on the leading end portion andincludes a transverse member with two wheels rotatably supported onopposite ends of the transverse member. A stem is fixed in perpendicularorientation relative to the transverse member and a handlebar isconnected to the stem. The leading end portion includes a head tube withat least one bearing housed therein, the bearing including an inner raceattached to the stem and an outer race attached to the head tube,wherein the inner and outer races include interfering projections thatlimit the rotation of the stem with respect to the frame.

A rear wheel assembly is pivotably disposed on the trailing end portion,wherein the wheel assembly pivots about an upwardly extending pivotaxis. The pivot axis is inclined forwardly with respect to the leadingand trailing end portions. The pivot axis is inclined forwardly withrespect to vertical between about 5 and about 25 degrees. The rear wheelassembly may include a caster pivotable about the pivot axis and ispreferably biased toward a centered position, wherein the caster isaligned with a centerline of the frame. The wheel assembly preferablyincludes an end stop that limits the extent to which the caster canpivot.

A resilient member is connected between the frame and a leading portionof the caster. The resilient member may be in the form of an extensionspring, for example. Means for adjusting the tension of the extensionspring may also be included. Preferably, a caster guard is disposed onthe frame forward of the caster. The caster guard may also contain atleast a portion of the extension spring therein.

Also contemplated is a method for inducing oversteer in a scooter duringa turn on a surface. The method comprises providing the scooter with arear wheel assembly pivotably disposed about a pivot axis on a trailingend portion of the scooter, the rear wheel assembly including a wheelrotatably mounted on an axle. The rear wheel assembly is biased toward acentered position, wherein the wheel is aligned with a centerline of thescooter. The axle is positioned rearward of the pivot axis such that alateral load generated against the wheel by the surface during the turncauses the rear wheel assembly to pivot away from the centered positionin a direction opposite the turn thereby inducing oversteer. The methodmay further comprise limiting the extent to which the rear wheelassembly can pivot. The scooter may further include a deck and themethod further comprising maintaining the deck at a generally levelattitude relative to the surface during the turn.

The foregoing and other features, utilities, and advantages of the driftscooter will be apparent from the following more particular descriptionof the embodiments as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of a drift scooterand together with the description, serve to explain the principles andoperation thereof. Like items in the drawings are generally referred tousing the same numerical reference.

FIG. 1 is a perspective view of a scooter according to an exemplaryembodiment;

FIG. 2 is a right side elevation view of the scooter shown in FIG. 1;

FIG. 3 is a bottom plan view of the scooter shown in FIGS. 1 and 2;

FIG. 4 is a partial front view of the scooter showing the steeringassembly partially exploded;

FIG. 5 is a partial bottom view of the steering assembly shown in FIG. 4with the transverse member removed for clarity;

FIG. 6 is an enlarged partial side view of the frame and rear wheelassembly;

FIG. 7 is a cross-section of the rear wheel assembly taken about line7-7 shown in FIG. 6;

FIG. 8A is a schematic representation of the drift scooter as viewedfrom above illustrating the scooter traveling straight;

FIG. 8B is a schematic representation of the drift scooter as viewedfrom above illustrating the initiation of a right turn;

FIG. 8C is a schematic representation of the drift scooter as viewedfrom above illustrating oversteer induced by the pivoting rear wheelassembly; and

FIG. 8D is a schematic representation of the drift scooter as viewedfrom above illustrating the steering assembly turned to counteractoversteer induced by the pivoting wheel assembly.

DETAILED DESCRIPTION

Described herein is a drift scooter that provides a new and excitingcornering sensation enhancing a rider's enjoyment. The design inducesoversteer in the scooter as it turns thereby providing the sensationthat the scooter is sliding or drifting. The sliding or driftingsensation simulates a feeling of extreme speed. Furthermore, controllingthe drift through counter-steering provides an entertaining challengefor the rider.

FIG. 1 illustrates a drift scooter 5 according to an exemplaryembodiment. Scooter 5 includes a frame 10 with a deck 20 disposedthereon. Pivotably supported on a leading end portion 12 of frame 10 isa steering assembly 30. Steering assembly 30 includes handlebar 32 witha pair of handgrips 31′ and 31″ disposed on opposite ends thereof.Handlebar 32 is secured to steering tube 34 by clamp 36. A transversemember 42 is connected to the handlebars 32 via the steering tube 34.Rotatably supported on opposite ends of transverse member 42 are frontwheels 38′ and 38″. Rear wheel assembly 60 is rotatably disposed ontrailing end portion 14 of frame 10. It can be appreciated from FIG. 1that the scooter disclosed herein is preferably a three wheeled vehiclehaving two wheels located on the leading end of the scooter and a singlewheel located on the trailing end of the scooter. A rider may stand ondeck 20 while grasping handgrips 31′ and 31″. As with a conventionalscooter, the rider may propel the scooter by kicking with one foot. Itshould also be understood that as a rider rotates handlebar 32 relativeto frame 10 the entire steering assembly 30, including front wheels 38′and 38″, also rotates in order to steer the scooter as desired.

As perhaps best shown in FIG. 2, deck 20 includes a convex portion 22,which provides a contoured surface for the rider to brace against duringdrifting maneuvers which are explained more fully below. Leading endportion 12 includes head tube 15 through which handlebars 32 areconnected to transverse member 42. With reference to both FIGS. 1 and 2,frame 10 arcuately extends upwards to meet head tube 15, thus loweringthe center of gravity of the scooter. Frame 10 also includes wheel guard18 disposed in front of rear wheel assembly 60. Wheel guard 18 protectsrear wheel assembly 60 from impact with curbs and other obstacles whichcould potentially cause damage to rear wheel assembly 60. As shown here,wheel guard 18 is a ramp shaped member capable of deflecting obstaclesaway from the mounting portion of rear wheel assembly 60 such thatobstacles may slide over the wheel guard 18 as well as rear wheelassembly 60 without directly impacting the wheel assembly. With furtherreference to FIG. 3, wheel guard 18 also has a tubular constructionwhich may also house a centering spring and tension adjuster for therear wheel assembly 60 as explained more fully below.

Also shown in FIG. 3, frame 10 includes opposed leading and trailing endportions, 12 and 14 respectively, with a longitudinal portion 13extending therebetween. Extending transversely from longitudinal portion13 is a plurality of rib supports 16 that support deck 20. In thisembodiment, deck 20 is secured to rib supports 16 with a plurality offasteners 24. Frame 10 may be formed of metal such as steel or aluminum.Deck 20 may be formed from plastic, wood, or light metals, or the like.

FIG. 4 is a partial exploded view illustrating how steering assembly 30is assembled with head tube 15. Stem 44 is fixed in perpendicularorientation relative to transverse member 42. Stem 44 may, for example,be welded to transverse member 42. When assembled, stem 44 extendsthrough head tube 15 and is secured in place with bearing nut 57. Stem44 includes a lower inner bearing race 48 which receives lower bearing53. Head tube 15 includes lower and upper outer bearing races 52 and 54respectively. Lower bearing race 52 receives lower bearing 53 and upperouter bearing race 54 receives upper bearing 55. Bearing nut 57 includesan inner race which engages upper bearing 55. Bearing nut 57 engagesthreads 46 disposed on the upper end of stem 44. The arrangement ofinner and outer bearing races and upper and lower bearings is well knownin the art and is typically used on bicycles. However, in this caselower inner bearing race 48 is preferably permanently attached to stem44 by welding or otherwise so that it cannot rotate with respect to stem44. Similarly, lower outer bearing race 52 is fixed to head tube 15 witha rivet 59 so that it cannot rotate with respect to head tube 15.

Referring now to FIG. 5, which shows the lower bearing races 48 and 52,lower bearing race 48 includes a pair of outwardly extending protrusions43′ and 43″. Lower outer bearing race 52 includes a pair of inwardlyextending protrusions 58′ and 58″. One of ordinary skill in the art willrecognize that as stem 44 is rotated relative to head tube 15protrusions 43′ and 43″ will interfere with protrusions 58′ and 58″.Thus, the left and right steering rotation of the steering assembly 30relative to frame 10 is limited. Briefly returning to FIGS. 1 and 2 itcan be appreciated that the rotation of steering assembly 30 isadvantageously limited in order to prevent wheels 38′ and 38″ frominterfering with frame 10 or deck 20.

FIG. 6 illustrates a partial side view in partial cross-section of therear wheel assembly 60 and a resilient member in the form of anextension spring 80 along with associated mounting components andfeatures. In this embodiment, rear wheel assembly 60 is in the form of acaster which includes caster frame 64, rear wheel 62, and an axel 66that supports rear wheel 62 in frame 64. Rear wheel assembly 60 ispivotably mounted on a spindle 72 which extends from trailing endportion 14. Caster frame 64 is mounted to spindle 72 with a suitablefastener 68. As can be appreciated in FIG. 6, rear wheel assembly 60pivots about axis “A” which is inclined forwardly with respect to theleading and trailing end portions of frame 10. Axis “A” may be inclinedat between about 5 and about 25 degrees, but preferably at about 18degrees. The inclination of axis “A” has a tendency to center rear wheelassembly 60 along longitudinal frame portion 13. Thus, the rear wheelassembly is biased towards a centered position where the caster isaligned with a longitudinal axis of the frame. Also, by angling thecaster, side to side motion of the caster tends to cause forwardpropulsion. This may be accomplished by weaving the scooter back andforth, for example.

Extension spring 80 acts on caster frame 64 in order to further bias therear wheel assembly 60 toward the centered position. Extension spring 80includes hook portions 82 and 84 which connect the spring between frame10 and caster frame 64. Hook portion 82 connects to ear 63 (see FIG. 7)and hook portion 84 connects to frame 10 via tension adjuster 90.Tension adjuster 90 includes mounting bracket 92 which is attached toframe 10 through an opening in wheel guard 18. Threadably engagedthrough mounting bracket 92 is an adjustment screw 94 which has aconnector loop 96 rotatably disposed thereon. Hook portion 84 isconnected to loop 96 so that as adjustment screw 94 is threaded in orout with respect to mounting bracket 92 the tension of extension spring80 is accordingly decreased or increased. It should be appreciated thatwhile the resilient member has been described here as an extensionspring other structures for biasing the caster to the centered positionmay be employed. For example, a torsion spring may be disposed aboutspindle 72 which engages the caster frame 64. Also, it is contemplatedthat compression springs could be arranged to bias the rear wheelassembly 60 toward the centered position. As mentioned above, wheelguard 18 houses extension spring 80 and tension adjuster 90. Thus, wheelguard 18 also protects the tensioning components.

With reference to FIG. 7, the rotation of rear wheel assembly 60 aboutaxis “A” is limited by an end stop 74 extending from frame 10. End stop74 extends into slot 65 which is formed in caster frame 64. As can beseen in the figure, slot 65 extends arcuately around a portion of thecircumference of the caster frame. Thus, rotation of the rear wheelassembly 60 is limited by the length of the arcuate slot 65.

Having described the structure of the drift scooter, the operation ofthe scooter can now be better appreciated. FIGS. 8A-8D are schematicrepresentations of the scooter as viewed from above during variousstages of a right hand drift turn. In FIG. 8A scooter 5 is showntraveling straight with the transverse member 42 and front wheels 38′and 38″ oriented perpendicular to frame 10 while rear wheel assembly 60is centered with respect to frame 10. FIG. 8B shows scooter 5 at thepoint of initiating a right-hand turn. Transverse member 42 and frontwheels 38′ and 38″ are rotated to the right via the handle bars. As thescooter begins to turn, a lateral load or centripetal force “F” isexerted on contact patch 67 of rear wheel 62. It should be understoodthat contact patch 67 is offset from pivot axis “A” such that thecentripetal force “F” acting on contact patch 67 causes rear wheelassembly 60 to rotate around pivot axis “A” such as shown in FIG. 8C.Thus, depending on the amount of centering bias exerted on rear wheelassembly 60 the wheel assembly will rotate about pivot axis “A” as thescooter generates enough centripetal force to overcome the centeringbias. As shown in FIG. 8C, oversteer is induced in the scooter as rearwheel assembly 60 pivots in a direction opposite to the turn. Asexplained above with respect to FIG. 6, the tension in extension spring80 may be adjusted. Increasing the tension in extension spring 80 willdecrease the amount of oversteer and decreasing the tension willincrease the amount of oversteer. Finally, as shown in FIG. 8Dtransverse member 42 and wheels 38′ and 38″ are rotated away from theturn (to the left) in order to compensate for the oversteer induced byrear wheel assembly 60. This technique of compensating for oversteer ina vehicle is often referred to as counter-steering. Convex portion 22 ofdeck 20 mentioned above provides a contoured or banked surface for therider to stand against during a drift as described above. Note that thethree wheeled configuration of the scooter with two front wheelfacilitates the drift maneuvers described above while maintaining deck20 at a generally parallel or level attitude with respect to the ridingsurface.

Methods relating to the above described drift scooter are alsocontemplated. The methods thus encompass the steps inherent in the abovedescribed mechanical structures and operation thereof. Broadly, onemethod could include inducing oversteer in a scooter during a turn on asurface. More specifically, the method could comprise providing thescooter with a rear wheel assembly pivotably disposed about a pivot axison a trailing end portion of the scooter, the rear wheel assemblyincluding a wheel rotatably mounted on an axle. The rear wheel assemblybeing biased toward a centered position, wherein the wheel is alignedwith a centerline of the scooter. The axle is positioned rearward of thepivot axis such that a lateral load generated against the wheel by thesurface during the turn causes the rear wheel assembly to pivot awayfrom the centered position in a direction opposite the turn therebyinducing oversteer. The method may further comprise limiting the extentto which the rear wheel assembly can pivot. The scooter may furtherinclude a deck and the method further comprising maintaining the deck ata generally level attitude relative to the surface during the turn.

Accordingly, the drift scooter has been described with some degree ofparticularity directed to the exemplary embodiment. It should beappreciated, though, that the present invention is defined by thefollowing claims construed in light of the prior art so thatmodifications or changes may be made to the exemplary embodimentswithout departing from the inventive concepts contained herein.

We claim:
 1. A scooter, comprising: A. a longitudinal frame includingopposed leading and trailing end portions; B. a steering assemblypivotably disposed on said leading end portion, said steering assemblyincluding: i. a transverse member, ii. two wheels rotatably supported onopposite ends of said transverse member, iii. a stem fixed inperpendicular orientation relative to said transverse member, and iv. ahandlebar connected to said stem; and C. a rear wheel assembly pivotablydisposed on said trailing end portion, wherein said wheel assemblypivots about an upwardly extending pivot axis.
 2. A scooter according toclaim 1, including a deck extending along at least a portion of saidframe, wherein a top surface of said deck includes a convex portion. 3.A scooter according to claim 1, wherein said rear wheel assemblyincludes a caster pivotable about said pivot axis.
 4. A scooteraccording to claim 3, wherein said caster is biased toward a centeredposition, wherein said caster is aligned with a centerline of saidframe.
 5. A scooter according to claim 3, including an end stop limitingthe extent to which said caster can pivot.
 6. A scooter according toclaim 3, wherein said pivot axis is inclined forwardly with respect tosaid leading and trailing end portions.
 7. A scooter according to claim6, including a resilient member connected between the frame and aleading portion of said caster.
 8. A scooter according to claim 7,including a guard located in front of the caster.
 9. A scooter accordingto claim 7, wherein said resilient member is an extension spring.
 10. Ascooter according to claim 9, including means for adjusting the tensionof said extension spring.
 11. A scooter, comprising: A. a longitudinalframe including opposed leading and trailing end portions; B. a deckextending along at least a majority of said frame; C. a steeringassembly pivotably disposed on said leading end portion, said steeringassembly including: i. a transverse member, ii. two wheels rotatablysupported on opposite ends of said transverse member, iii. a stem fixedin perpendicular orientation relative to said transverse member, and iv.a handlebar connected to said stem; D. a single caster pivotablydisposed on said trailing end portion, wherein said caster pivots aboutan upwardly extending pivot axis that is inclined forwardly with respectto said leading and trailing end portions; and E. an extension springconnected between the frame and a leading portion of said caster.
 12. Ascooter according to claim 11, wherein a top surface of said deckincludes a convex portion.
 13. A scooter according to claim 11,including a caster guard disposed on said frame forward of said caster,and wherein at least a portion of said extension spring is containedwithin said caster guard.
 14. A scooter according to claim 11, includingmeans for adjusting the tension of said extension spring.
 15. A scooteraccording to claim 11, including an end stop limiting the extent towhich said caster can pivot.
 16. A scooter according to claim 11,wherein said pivot axis is inclined forwardly with respect to verticalbetween about 5 and about 25 degrees.
 17. A scooter according to claim11, wherein said leading end portion includes a head tube with at leastone bearing housed therein, said bearing including an inner raceattached to said stem and an outer race attached to said head tube,wherein said inner and outer races include interfering projections thatlimit the rotation of said stem with respect to said frame.
 18. A methodfor inducing oversteer in a scooter during a turn on a surface, themethod comprising: providing the scooter with a rear wheel assemblypivotably disposed about a pivot axis on a trailing end portion of thescooter, said rear wheel assembly including a wheel rotatably mounted onan axle; biasing said rear wheel assembly toward a centered position,wherein said wheel is aligned with a centerline of the scooter; andpositioning said axle rearward of said pivot axis such that a lateralload generated against said wheel by the surface during the turn causesthe rear wheel assembly to pivot away from the centered position in adirection opposite the turn thereby inducing oversteer.
 19. The methodaccording to claim 18, further comprising limiting the extent to whichsaid rear wheel assembly can pivot.
 20. The method according to claim18, wherein said scooter includes a deck and further comprisingmaintaining said deck at a generally level attitude relative to thesurface during the turn.